API Standard 650

1 API Stan ndard rd 650. Welde ed Tank ks for Oil O Stora age TWELFTH EDITION. E | MARC. CH 2013 | 498 PAGES | $ | PRODUCT. T NO. C65012. This Standard establishess minimum req quirements for Forr ordering inforrmation: material, deesign, fabrication, erection, and a inspection n for vertical, cylindrical, above eground, closeed- and open-ttop, Onlline: welded storrage tanks in various v sizes and a capacitiess for internal pressures approxximating atmo ospheric pressure Phoone: 1-800-854-7179. (internal preessures not exxceeding the weight w of the ro oof (Toll-freee in the and Canada). plates), but a higher interrnal pressure is i permitted when w additional reequirements area met. This Standard s applies (+1) 3033-397-7056. only to tankks whose entire bottom is un niformly suppoorted (Local an nd Internationa al). and to tanks in non-refrig gerated service e that have a maximum design d tempera ature of 93 C.

2 C (200 F) or less. l Faxx: (+1) 303. 3-397-2740. This Standard is designed d to provide industry with tan nks of adequate sa afety and reassonable econo omy for use in the APII members receeive a 30% disscount where applicable. storage of petroleum, p pettroleum products, and otherr liquid produucts. This Standard does nott present or establish a fixed series off allowable tan nk sizes; instead, it is intended to permit the Purchaser to select s whatever size tank may best meet his needs. This Standard is intended to help Purchasers and Manu ufacturers in ordering, fabricating, and erecting tank ks; it is not inte ended to prohibit Purchasers P and Manufacturrers from purchasing or fabricating tanks that me eet specifications other than those t containeed in this Standard . Contents Page 1 Scope ..1-1. General ..1-1. Limitations ..1-4. Responsibilities ..1-4. Documentation Requirements.

3 1-5. Formulas..1-5. 2 Normative References..2-1. 3 Terms and Definitions ..3-1. 4 Materials ..4-1. General ..4-1. Plates ..4-2. Sheets ..4-9. Structural Shapes ..4-9. Piping and Forgings ..4-14. Flanges ..4-15. Bolting..4-17. Welding Electrodes ..4-17. Gaskets ..4-17. 5 Design ..5-1. Joints..5-1. Design Considerations ..5-9. Special Considerations..5-12. Bottom Plates..5-14. Annular Bottom Plates ..5-15. Shell Design ..5-17. Shell Openings..5-27. Shell Attachments and Tank Appurtenances ..5-64. Top and Intermediate Stiffening Rings ..5-77. Roofs..5-86. Wind Load on Tanks (Overturning Stability) ..5-94. Tank Anchorage..5-96. 6 Fabrication ..6-1. General ..6-1. Shop Inspection..6-2. 7 Erection..7-1. General ..7-1. Details of Welding ..7-1. Examination, Inspection, and Repairs ..7-5. Repairs to Welds ..7-9. Dimensional Tolerances ..7-10. 8 Methods of Examining Joints ..8-1. Radiographic Method.

4 8-1. Magnetic Particle Examination ..8-5. Ultrasonic Examination..8-5. Liquid Penetrant Examination ..8-5. vii Page Visual Examination ..8-6. Vacuum Testing ..8-7. 9 Welding Procedure and Welder Qualifications ..9-1. Definitions ..9-1. Qualification of Welding Procedures ..9-1. Qualification of Welders ..9-2. Identification of Welded Joints ..9-3. 10 Marking ..10-1. Nameplates ..10-1. Division of Responsibility..10-3. Certification ..10-3. Annex A (normative) Optional Design Basis for Small Tanks .. A-1. Annex AL (normative) Aluminum Storage Tanks .. AL-1. Annex B (informative) Recommendations for Design and Construction of Foundations for Aboveground Oil Storage Tanks .. B-1. Annex C (normative) External Floating Roofs .. C-1. Annex D (informative) Inquiries and Suggestions for Change .. D-1. Annex E (normative) Seismic Design of Storage Tanks .. E-1. Annex EC (informative) Commentary on Annex E.

5 EC-1. Annex F (normative) Design of Tanks for Small Internal Pressures ..F-1. Annex G (normative) Structurally-Supported Aluminum Dome Roofs .. G-1. Annex H (normative) Internal Floating Roofs .. H-1. Annex I (normative) Undertank Leak Detection and Subgrade Protection.. I-1. Annex J (normative) Shop-Assembled Storage Tanks ..J-1. Annex K (informative) Sample Applications of the Variable-Design-Point Method to Determine Shell- plate Thickness .. K-1. Annex L (normative) API Standard 650 Storage Tank Data Sheet ..L-1. Annex M (normative) Requirements for Tanks Operating at Elevated Temperatures.. M-1. Annex N (normative) Use of New Materials That Are Not Identified .. N-1. Annex O (informative) Recommendations for Under-Bottom Connections .. O-1. Annex P (normative) Allowable External Loads on Tank Shell Openings .. P-1. Annex S (normative) Austenitic Stainless Steel Storage Tanks.

6 S-1. Annex SC (normative) Stainless and Carbon Steel Mixed Materials Storage Tanks.. SC-1. Annex T (informative) NDE Requirements Summary ..T-1. Annex U (normative) Ultrasonic Examination in Lieu of Radiography .. U-1. Annex V (normative) Design of Storage Tanks for External Pressure .. V-1. Annex W (normative) Commercial and Documentation Recommendations .. W-1. Annex X (normative) Duplex Stainless Steel Storage Tanks .. X-1. Annex Y (informative) API Monogram .. Y-1. viii Page Figures Minimum Permissible Design Metal Temperature for Materials Used in Tank Shells without Impact Testing (SI) ..4-7. Minimum Permissible Design Metal Temperature for Materials Used in Tank Shells without Impact Testing (USC) ..4-8. Isothermal Lines of Lowest One-Day Mean Temperatures ( F) [ C = ( F 32)]..4-10. Governing Thickness for Impact Test Determination of Shell Nozzle and Manhole Materials.

7 4-16. Typical Vertical Shell Joints ..5-3. Typical Horizontal Shell Joints ..5-4. Typical Roof and Bottom Joints ..5-5. Method for Preparing Lap-welded Bottom Plates under Tank Shell ..5-6. Detail of Double Fillet-groove Weld for Annular Bottom Plates with a Nominal Thickness Greater than 13 mm (1/2 in.)..5-6. Spacing of Three- plate Welds at Annular Plates ..5-7. Storage Tank ..5-12. Drip Ring (Suggested Detail)..5-14. Minimum Weld Requirements for Openings in Shells According to ..5-28. Shell Manhole ..5-34. Details of Shell Manholes and Nozzles ..5-35. Shell Nozzles..5-36. Minimum Spacing of Welds and Extent of Related Radiographic Examination ..5-50. Shell Nozzle Flanges ..5-52. Area Coefficient for Determining Minimum Reinforcement of Flush-type Cleanout Fittings ..5-54. Flush-Type Cleanout Fittings ..5-55. Flush-type Cleanout Fitting Supports ..5-56. Flush-type Shell Connection.

8 5-60. Rotation of Shell Connection ..5-63. Roof Manholes ..5-67. Rectangular Roof Openings with Flanged Covers ..5-71. Rectangular Roof Openings with Hinged Cover..5-72. Flanged Roof Nozzles ..5-73. Threaded Roof Nozzles ..5-73. Drawoff Sump ..5-73. Scaffold Cable Support ..5-74. Grounding Lug ..5-77. Typical Stiffening-ring Sections for Tank Shells..5-80. Stairway Opening through Stiffening Ring ..5-83. Some Acceptable Column Base Details ..5-91. Overturning Check for Unanchored Tanks ..5-94. Shaping of Plates ..6-2. Radiographic Requirements for Tank Shells ..8-2. Manufacturer's Nameplate ..10-1. Manufacturer's Certification Letter ..10-3. Cover plate Thickness for Shell Manholes and Cleanout Fittings .. AL-13. Flange plate Thickness for Shell Manholes and Cleanout Fittings .. AL-14. Bottom Reinforcing plate Thickness for Cleanout Fittings.. AL-15. Stresses in Roof Plates .. AL-18.

9 Example of Foundation with Concrete Ringwall .. B-4. Example of Foundation with Crushed Stone Ringwall .. B-5. Coefficient Ci .. E-13. Maximum Earthquake Response Spectrum .. EC-4. Earthquake Response Spectrum Notation .. EC-4. ix Page Site Specific Response Spectrum .. EC-5. Deterministic Lower Limit on MCE Response Spectrum .. EC-5. Relationship of Probabilistic and Deterministic Response Spectra .. EC-6. Sloshing Factor, Ks .. EC-7. Design Response Spectra for Ground-Supported Liquid Storage Tanks .. EC-8. Effective Weight of Liquid Ratio .. EC-10. Center of Action of Effective Forces .. EC-10. Anchor Strap Attachment to Shell .. EC-12. Overturning Moment .. EC-12. Annex F Decision Tree..F-2. Permissible Details of Compression Rings..F-3. Data Sheet for a Structurally-Supported Aluminum Dome Added to an Existing Tank.. G-2. Typical Roof Nozzle .. G-9. Concrete Ringwall with Undertank Lead Detection at the Tank Perimeter (Typical Arrangement).

10 I-2. Crushed Stone Ringwall with Undertank Leak Detection at the Tank Perimeter (Typical Arrangement) .. I-3. Earthen Foundation with Undertank Leak Detection at the Tank Perimeter (Typical Arrangement) .. I-3. Double Steel Bottom with Leak Detection at the Tank Perimeter (Typical Arrangement) .. I-3. Double Steel Bottom with Leak Detection at the Tank Perimeter (Typical Arrangement) .. I-5. Reinforced Concrete Slab with Leak Detection at the Perimeter (Typical Arrangement) .. I-5. Reinforced Concrete Slab .. I-6. Typical Drawoff Sump .. I-7. Center Sump for Downward-Sloped Bottom.. I-7. Typical Leak Detection Wells .. I-8. Tanks Supported by Grillage Members (General Arrangement).. I-9. Example of Under-Bottom Connection with Concrete Ringwall Foundation .. O-3. Example of Under-Bottom Connection with Concrete Ringwall Foundation and Improved Tank Bottom and Shell Support .. O-4.